Economist, May 10, 2014 (I)

choi

This issue has
(a) one preview:

How better rice could save lives  A Second Green Revolution. Technological breakthroughs in rie will boost harvests and cut poverty. They deserve support.

, and (b) a three-page article (plus a side bar, see the following posting):

BRIEFING The new green revolution | A Bigger Rice Bowl. Another green revolution is stirring in the world’s paddy fields
(“Flood-resistant rice is now spreading * * * Five years after the first field trial, 5m farmers across the world are planting more than a dozen varieties of rice with flood-resistant genes, collectively called ‘Sub 1.’ * * * If all goes well, over the next few years plants that tolerate drought, salinity and extreme heat will revolutionise the cultivation of mankind’s most important source of calories”)

My comment:
(a) There is no need to read either. And what the future holds for the upcoming rice varieties we can wait to find out.

(b) I will mention the discovery of flood-resistant genes, in a locus called Sub-1.
(i) Xu et al, Sub1A Is an Ethylene-Response-Factor-Like Gene That Confers Submergence Tolerance to Rice. Nature, 442, 705-708 (2006).
www.nature.com/nature/journal/v442/n7103/full/nature04920.html
(abstract only, for nonsubscribers)
(A) “O sativa ssp. indica”

ssp = subspecies
Oryza sativa has two subspecies: indica (long grain) and japonica (short grain)
(B) “Two of these genes, Sub1B and Sub1C, are invariably present in the Sub1 region of all rice accessions analysed. In contrast, the presence of Sub1A is variable. A survey identified two alleles within those indica varieties that possess this gene: a tolerance-specific allele named Sub1A-1 and an intolerance-specific allele named Sub1A-2. Overexpression of Sub1A-1 in a submergence-intolerant O. sativa ssp. japonica conferred enhanced tolerance to the plants, downregulation of Sub1C and upregulation of Alcohol dehydrogenase 1 (Adh1), indicating that Sub1A-1 is a primary determinant of submergence tolerance.”

The first two sentence said that all rice cultivars, whether tolerant to submergence or not, have Sub1B and Sub1C--the difference lying in Sub1A. Sentence 3 indicated Sub1A had two alleles Sub1A-1 and Sub1A-1.

What is done to make a gene overexpression? By transgenics: injecting a gene (Sub1A-1 here, in thousands of copies, in part because it is impossible to isolate a single copy) into the cells of of intolerant cultivars, the gene will integrate into the DNA of the recipient, thousand of copies in tandem, whose expression will be more than that of a single copy of the same gene.
(C) The full text of the nature report (from the co-author Pamela C Ronald; though there is no need to read it):

indica.ucdavis.edu/news/new-flood-tolerant-rice-offers-relief-for-worlds
(D) The following, from (E) to the end, is to explain “Ethylene Response Factors.”
(E) Among plant hormones, ethylene is the only that is gaseous. For its functions, read
Ethylene: The Ripening Hormone. Postharvest Information Network, Tree Fruit Research & Extension Center, Washington State University, undated.
postharvest.tfrec.wsu.edu/pages/PC2000F
(F) Research is still on-going, regarding the molecular mechanism of ethylene signal transduction from outside the cell to nucleus.

An ethylene molecule permeates through cell membrane and bind to a receptor on the endoplasmic reticulum, which triggers the release of EIN2 (Ethylene INsensitive 2), whose cleaved carboxyl terminus departs cytosol for the nucleus.
Wen X et al, Activation of Ethylene Signaling Is Mediated by Nuclear Translocation of the Cleaved EIN2 carboxyl terminus. Cell Research, 22: 1613-1616 (2012).
www.nature.com/cr/journal/v22/n11/full/cr2012145a.html

Eventually “Ethylene-response factor (ERF) proteins, which were known formerly as ethylene-responsive element binding proteins (EREBPs), function as trans-factors at the last step of transduction in the nucleus.”
Wang AD et al, MdERFs, Two Ethylene-Response Factors Involved in Apple Fruit Ripening. Journal of Experimental Botany, 12: 3743-3748.
jxb.oxfordjournals.org/content/58/13/3743.full

I have to mention ERFs’ former name because Wikipedia has a page under the former name, though not informative at all.

choi

BRIEFING  Rental markets | Combine Harvesters. Seeds are not the only miracle components of the new green revolution. Rental markets for equipment are almost as remarkable. www.economist.com/news/briefing/ ... tion-rental-markets